Hey guys,
I'm working on a 2001 Maxima for a friend. He brought it to me because it is running rough and is down on power. I discovered that two of the cylinders in the rear bank are not getting spark by unplugging the coil packs one by one and looking for a change in rpm. Two of the rear coil packs made no change in how it ran so I replaced them. While I was in there, I changed spark plugs and those two were saturated with gasoline so I know there is fuel. Got her all buttoned up, stared up, no change. Did the unplug thing again, still missing those 2 cylinders.........

I don't know what to do next, any advice? I read a lot about coil packs going out so I thought I was on the money. Do these things have an ignition module that goes out? or is there a way to test the coil packs?

Any help is greatly appreciated!

 

yes test them by testing the resistance (search on here for how) or better - swap them with another coil in the same bank and see if the non sparking cylinder changes

 

ok I will do that this evening after work. Thanks.

 

If its the coil pack ONLY replace with OEM. I learned the hard way due waiting on dealership to get stock. I used aftermarket and it misfired until car warmed up.

 

Dammit. Ok I got the replacements at NAPA. I'll try swapping the known good rear coil and see what gives.

 

some of the ones being sold by the local stores are oem repackaged. advance auto rear coils are oem hitachi (at least they were a few months back) the front ones are not they aare made in poland. also I believe beck/arnley are repackaged oem from japan.

 

Napa is what I bought and misfired and cold starts. Returned it when my OEM came in and no issues.

 

well I've ruled out the coil packs.... I swapped the known good one for a suspected faulty one and no change. pulled the plug and it was SOAKED in gasoline. I started the car with the pack out with a spark plug and it is working. I went ahead and pulled the plenum, the injector on that cyl is wet with gas on the outside? I pulled all six, going to take them in for a clean and test. Am I on the right track?

 

well just heard from Napa, 2 injectors failed! I'll have new ones in the morning, hopefully it will be the end of this issue!

 

Well FML. Still runs like poo. I did notice quite a bit of oily residue in the intake, and a little on the MAF. Can you clean a MAF without damaging it?

 

Get a can of CRC MAF cleaner...should do the trick for that..could the cylinders have lost compression?

 

Grabbed the MAF cleaner, tried that. Didn't work. I told the owner of the car he's probably better off taking it to a real mechanic as I don't have time/ patience for this right now. Judging by the blowby that's evident in the intake, this motor may need to be rebuilt, which sucks, he paid a couple grand to have it installed when the original one went.

 

Blow by and oil collection in the manifold is normal. Have you checked the replacement coils for spark? If the coils have been replaced but still arent sparking, and a known good coil does not produce spark when swapped, you need to check for voltage at the coil. If you have a somewhat good voltmeter you can probe the connector and watch for the signal from the ECU. If the coils arent getting a signal you wont have any spark, if there is no signal you either have fried coil drivers on the ECU or a wiring issue.